Preparation

Puree first 7 ingredients in processor until
paste forms. Cook in large pot over medium heat until aromatic, stirring often, about
10 minutes. Add tomato paste. Cook until mixture starts to darken and brown, stirring
often, about 5 minutes longer.

Add broth, brown sugar, lime leaves, and cardamom. Simmer 10 minutes, stirring often and scraping up browned bits. DO AHEAD Can be made 2 days ahead. Cool, cover, and chill. Bring to simmer before continuing.

Add sweet potatoes, russet potatoes, coconut, carrots, tomatoes, 1 teaspoon salt, and 1/4 teaspoon pepper to mixture in pot. Bring to boil, then reduce heat to medium low. Cover and simmer until vegetables are tender, stirring occasionally, about 25 minutes. Add spinach, if desired, and cook until wilted, about 3 minutes. Season with salt and pepper. Discard lime leaves and cardamom. Transfer curry to bowl; garnish with cilantro and serve.